Paper article and method of manufacture



May 1, 1928. 1,668,349

- E. G. BAUM PAPER ARTICLE AND METHOD OF MANUFACTURE Filed March 22.1926 Patented May 1, 1928.

UNITED STATES PATENT OFFICE.

EWALD G. BAUM,

OF NATICK, MASSACHUSETTS, ASSIGNOR, BY MESNE ASSIGNMENTS,

IORATION OF MASSACHUSETTS.

PAPER ARTICLE AND METHOD OF MANUFACTURE.

Application filed March 22, 1926. Serial No. 96,503.

This invention relates to articles of cellulosic material and a methodof manufacture, more especially of such articles formed up from papersheets, as, for example, certain forms of bottle caps or'closures. Moreparticularly it relates to such articles and their formation whereresistance to deformation in the presence of moisture is desirable ornecessary.

It has been found that when such articles are formed. by pressing sheetsof paper out of their normally flat condition there is a strong tendencyfor such articles to flatten out somewhat under the action of moisture,even though the sheet material be quite thoroughly treated withwaterproofing material, and where milk bottle caps are so made, thesecaps being provided with pouring lip housing portions, as shown, forexample, in my-Reissue Patent No. 15,491 dated November 21, 1922, forbottle caps, this tendency, if not counteracted, causes the marginalportions thereof to flare so that they do not properly engage thebottle. The caps then do not hold to the bOl'r' tles with suflicienttenacity and the contents are not always completely sealed.

By the method of the however, the structure 0 the paper is so somodified over at least those portions where flattening would be likelyto be detrimental, that such flattening tendency is quite effectuallyprevented. In general the method comprises .a preliminary treatment ofthe paper by which the cellulosic fibers are swelled and softened and bywhich the de sired waterproofing compounds are incorporated thereinprior to the forming of the aper into the article, and after thispreiminary treatment the subjection of the material, preferably in theprocess of formation, to such heavy pressure, at least over that portionor portions where flattening is to be prevented, that the fibers arecompacted together and the fibers of successive overlapping layersinterfelted so as to form with the waterproofing agent a dense, hornlike, translucent structure inthe desired sha e quite different from thestructure of tiie paper sheet before being subjected to this pressure.

Present invention,

For a more complete understanding of this invention reference may be hadto the accompanying drawings showing the application of the method to aform of a milk bottle cap somewhat like that shown in my reissued patenthereinbefore referred to. In these drawings,

Figure 1 is a plan of a blank from which the cap is to be formed.

Figures 2, 3, 4 and 5 are detail sections showing successive positionsof the dies relative to each other and to the blank as it is beingformed into a cap.

Figures 6 and 7 are elevation and plan Views, respectively, of apartially formed cap corresponding to that illustrated in Figure 4.

Figure 8 is a detail section on line 8-8 of Fi ure 6; I

igure 9 is a side elevation of a fully formed cap.

Figure 10 is a detail section on line 1010 of Figure 9.

The paper stock employed for this process should have high absorptivequalities and should be of uniform thickness and of a strength as nearas possible the same across the sheet as in its lengthwise direction.The paper is blanked out to the form required to make up the article andeither before or after the blanking operation, is subjected to thefollowing steps.

First, it is treated with water which it should be capable of absorbingfreely, the water being applied to the paper under such conditions oftime pressure and temperature as are found most suitable with theparticular stock being employed. The warmer the water the easier thepaper absorbs it under ordinary conditions. If the water is warm thepressure or time of treatment or both may be reduced, or the treatmentmay be prolonged under lower pressure or temperature conditions or both.The treatment should be sufiiciently thorou 11, however, to cause thecellulosic fibers 0% the paper to swell and soften to a material extent.The moistened paper should be allowed to stand a suflicienttime so thatthe moisture becomes uniformly spread' through its tex 'ture, Ordinarilybut aiew minutes is necessary for this, the time necessary dependinglargely on the particular paper stock being employed and somewhat alsoon the moistening methods which may have been used. The paper shouldthen be passed through a waterproofing compound preferably at anelevated temperature. The compound which has been found most suitable inpractice comprises waxes, such, for example, as paraflin preferably withthe addition of a small amount of hardening wax such as carnauba orMontan wax. The particular composition of the wax may be varied to suitthe product and also somewhat to suit the stock being treated. When themoistened and swollen paper passes into this bath of wax which should beat a temperature above 212 F., as for example from approximately 235 F.to 240 F., a portion of the water in the material is converted intosteam and escapes and as the paper passes out from the melted wax thecondensation of steam which may remain in the paper draws in the meltedwax so as to impregnate its fibrous structure without destroying itstensile strength, and to fill the intercellular spaces of the paperwithout however causing the fibers to be shrunk and contracted to theirsubstantially dry condition.

After the sheet material is treated with the wax it is preferable topermit it to stand for some hours, say 24 or more, in a closedcontainer, the material then cooling and seasoning or tempering. Whenremoved from these containers it is in condition for the formingoperation. In the case of the formation of the bottle cap of the typehereinbefore described the operations to be carried out are shownsomewhat diagrammatically in the drawings. A waxed and tempered blank 1is placed upon the die member 10, shown in Figures 2 to 5, and the diemember 11 is brought down on its central portion as at 2, the blankbeing thus held in position for the further forming operations. Next thedie member 12 is brought down against the upper face of the blank,pressing it against the outer portion 13 of the die member 10. Next thedie member 14 is moved upwardly, as shown in Figure 4, forming up theupstanding wall 15 which is to engage the inner wall of the milk bottleabove the usual annular ledge therein on which the usual disk ofcardboard is placed.

Next the outer die member 16 is brought downwardlyto form the outermargin of the blank into the downwardly extending portion 17, shown bestin Figure 9, which bears against the outer face of the bottle pouringlip. The pressure exerted on the material by these dies is veryconsiderable,

being on the order of from 6,000 to 10,000

pounds per square inch for waxed paper approximately .028 inch thick or.022 inch thick before being softened and waxed, and the clearancesbetween the die members 12, 14 and 16 are so proportioned thatsubstantially this pressure is exerted on the material therebetween whenthe cap is being formed.

It will be noted that since the maximum diameter of the finished cap isvery inuch smaller than that of the blank from which it is formed, thematerial in the inner upstanding and in the outer downwardl extendingportions 15 and 17, respectively, must be gathered together inoverlapping layers, and where the material is treated as hcreinbeforedescribed prior to the forming operations this heavy pressure causesthese overlapping portions -to be pressed together resulting in more orless interfelting of the fibers in the contacting layers and compactingthe fibers and the wax into a dense, horn-like structure which is highlyresistant to the action of moisture.

Where articles of paper are formed up by pressing from. flat sheetmaterial there is a strong tendency for overlapping layers to separatesomewhat so that the material tends to flatten after formation, thistendency being particularly noticeable when the articles are subjectedto moisture conditions. If this should be permitted in the case of abottle cap of the type shown, it would result in the outer pouring liphousin wall flaring so that its lower edge woui d not properly engagethe outer side of the bottle and would also result in the inner wallengaging the inner wall of the bottle drawing away from close contactwith the bottle so that the sealing qualities of'the cap would be verygreatly lmpaired and its removal from the bottle would be rendered tooeasy for security. By the treatment herein outlined, however, thispouring lip housing,

which is of general channel shape in section, is maintained in propercondition with the opposite walls thereof in the form in which they areproduced by the dieing operation. It has been found in practice thatsuch a cap may be subjectedto water for an indefinite time withoutshowing any tendency for flattening of the cap or flaring of these wallsto occur. Preferably, though not necessarily, the upper portion of thepouring lip housing has radial corrugations since this constructionproduces added resiliency to the pouring lip housing portion so that itmay be pressed over the pouring lip and tightly engage it on oppositesides. Preferably also the heavy pressure is applied to substantiallythe entire aieaof the cap ineluding its central bore-covering portion,

the upstanding wall portions 20 which are formed to engage the innerwall of the bottle beneath the usual disk-receiving annular ledge,andthe annular portion 21 which is formed to seat on the upper face ofthis the pressure completely formed, while Figure 10 illus-. 'trates insection the condition of this portion of the cap after it has beensubjected to the heavy pressure so that it has been reduced to asubstantially homogeneous, translucent, horn-like structure ofsubstantially uniform thickness with the fibrous material of theoverlapping layers felted together. This horn-like structure of thematerial can not be produced by the use of a water treatment alone,apparently the wax or its equivalent waterproofing material beingnecessary to produce the. interfelting of the fibers under to which theyare subjected according to this method. This material also serves anImportant function in the formation of the wall portions 15 and 17 ofthe cap in that it acts as a lubricant betweenthe die members and thesheet material and prevents these members from tearing the material dueto their severe rubbing effect thereon during the forming operation. Italso acts as a binder for the fibers and the layers'in the finishedproduct.

Having thus described this invention it will be evident that variousmodifications and changes might be made therein without departing fromits spirit or scope as defined by the appended claims.

I claim:

1. An article formed up from sheet cellulosic material containing awaterproofing agent and having portions of the sheet in foldedoverlapping relation, said portions being compressed to substantiallyuniform thickness and presenting a dense horn-like structure resistantto opening up when subjected to moisture.

-2. An article comprising sheet cellulosic material having portionsthereof in overlapping relation, said portions presenting a dense,horny, mterfelted structure resistant to separation of the overlappingportions when subjected to moisture.

3. An article formed up from waxed sheet cellulosic material and havinga portion comprising folded layers of such sheet material interfeltedand compressed to a translucent, horn-like condition.

4. An article formed up from waxed sheet cellulosiqmaterial and having aportion com; prising folded layers of such sheet, such portion beingformed into a dense, horny structure retaining its folded conditionindefinitely when subjected to moisture.

7 and 8 is illustrated the 5. An article formed up from a sheet of waxedpaper and having a portion comprising folded layers of such sheet, saidportion belng compressed to form a dense, horny structure retainin itsfolded condition indefinitely when su jected to moisture.

6. A milk bottle cap having a bore-covering portion terminating in anupstanding port-ion enga cable with the inner wall of a milk bottle elowthe usual disk-receiving annular ledge therein, a portion formed tooverlie said ledge, a portion upstanding from said ledge-engagingportion to engage the inner wall of the bottle above said ledge, and amarginal downwardly turned portion engageable with the outer wall of thebottle,

said upstanding and downwardly turned.

portions presenting dense structure resistant to deformation whensubjected to moisture. v7. A milk bottle cap of waxed paper having abore-coverlng portion terminating in an upstanding portion engageablewith the inner wall of a milk bottlebelow the usual disk-receivingannular led 'e therein, a portion formed to overlie sai ledge, a portionupstanding from said ledge-engagin portion to engage the inner wall ofthe ottle above said ledge, and a marginal downwardly turned portionengageable with the Outer wall of the bottle, said upstanding anddownturned portions comprising layers of the waxed paper folded togetherand compacted to a dense, translucent, horn-likecondition resistant tounfolding in the presence of moisture.

8. A bottle cap having a pouring lip housing engageable with oppositesides of the bottle wall, the wall-engaging portions comprising foldedlayers of interfelting sheet horn-like material.

10. The step in the process of forming a waxed blank of moistenedcellulosic sheet material into an article having portions of the sheetin folded overlapping relation which comprises subjecting said portionsto pressure sufiiciently heavy to compact them to substantiallyhomogeneous rigid horn-like structure of substantially uniformthickness. f 11. The method which comprises swelling and softening ablank of fibrous sheet material, incorporating wax therein, and thenforming an article from the blank thus treated under pressuresulficiently heavy to comact the material together into a dense,

orny condition.

.12. The method which comprises treating a fibrous blank with water,passing the wet blank through a liquid wax heated to a temperature above212 F. and thereby vap0riz ing a portion of the water from said blank 5and saturating the blank with the Wax, permitting the blank thus treatedto temper, and then forming said blank to the desired EWALD G. BAUM.

